John Deere 4720 with 400CX loader

[fordboy]

Anyone out there running with a 400CX loader??? I am having some (what I feel are) issues. Per John Deere I am getting what they are calling cavitation of the hyd system. Where I have this issue is when I go to back drag with the bucket. Sometimes it will curl and lift the front of the tractor off the ground other times it just doesn't do anything. They are saying cavitation is not a problem. I say it isn't working the way it should! Comments please!